Thermosetting resin composition, prepreg, laminate and multilayer printed wiring board

ABSTRACT

Provided are a thermosetting resin composition having especially good compatibility and having dielectric properties (low dielectric constant and low dielectric dissipation factor) in a high frequency range, high adhesion to conductor, excellent heat resistance, high glass transition temperature, low thermal expansion coefficient and high flame retardancy, and a prepreg, a laminate and a multilayer printed wiring board using the resin composition. Specifically, the thermosetting resin composition contains (A) a polyphenylene ether derivative having an N-substituted maleimide structure-containing group and a structural unit represented by the following general formula (I) in one molecule, (B) at least one thermosetting resin selected from the group consisting of epoxy resins, cyanate resins and maleimide compounds, and (C) a phosphorus flame retardant: 
                         
wherein R 1  each independently represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a halogen atom, and x represents an integer of 0 to 4.

CROSS-REFERENCE TO RELATED APPLICTIONS

This application is a U.S. national phase application filed under 35U.S.C. § 371 of International Application No. PCT/JP2016/063497, filedApr. 28, 2016, designating the United States, which claims benefit ofthe filing date of JP 2015-093508, filed Apr. 30, 2015, which is herebyincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a thermosetting resin compositioncontaining a polyphenylene ether derivative, and to a prepreg, alaminate and a multilayer printed wiring board.

BACKGROUND ART

Signals used in mobile communication devices, such as a cell phone, basestation apparatuses for them, network infrastructure devices, such as aserver and a router, large-sized computers, and the like are beingincreased in the speed and capacity. In accordance with this, printedwiring boards mounted on these electronic devices are required to adaptto high-frequency signals, and a substrate material having excellentdielectric characteristics (low dielectric constant and low dielectricdissipation factor; hereinafter these may be referred to as highfrequency properties) in a high frequency range that enable reduction ofa transmission loss is demanded. Recently, as such applications thathandle high-frequency signals, practical realization and practical useplanning of novel systems that handle high-frequency wireless signals inan ITS field (in connection with automobiles and traffic systems) aswell as in a field of indoor short-distance communications systems, inaddition to the above-mentioned electronic devices, is being promoted,and in future, low transmission-loss substrate materials are expected tobe required for the printed wiring boards to be mounted on thesedevices.

Further, in view of the environmental problems encountered in recentyears, mounting of electronic parts using a lead-free solder andachieving flame retardancy free of a halogen are demanded, and thereforethe material for a printed wiring board is needed to have higher heatresistance and more excellent flame retardancy than conventional.

Conventionally, for a printed wiring board required to have a lowtransmission loss, a polyphenylene ether (PPE) resin has been used as aheat-resistant thermoplastic polymer excellent in high frequencyproperties. For example, a method of using a polyphenylene ether and athermosetting resin as combined has been proposed. Specifically, a resincomposition containing a polyphenylene ether and an epoxy resin (see,for example, PTL 1), a resin composition using a polyphenylene ether inconnection with a cyanate ester resin having a low dielectric constantamong thermosetting resins (see, for example, PTL 2) and the like havebeen disclosed.

However, the resin compositions described in the above-mentioned PTL's 1and 2 are unsatisfactory collectively in the high frequency propertiesin a GHz region, the adhesion to conductor, the low thermal expansioncoefficient, and the flame retardancy. In addition, the compatibility ofpolyphenylene ether with a thermosetting resin is low, and therefore theheat resistance of the resultant resin composition may often lower.

Meanwhile, the present inventors have proposed a resin compositionhaving a polyphenylene ether resin and a polybutadiene resin as a base,wherein the resin composition can be improved in the compatibility, heatresistance, low thermal expansion coefficient, adhesion to conductor,and the like by performing semi-IPN (semi-interpenetrating network)formation in the production stage (A-stage) of producing a resincomposition containing an organic solvent (for example, PTL 3). However,the substrate material recently used for a printed wiring board is notonly required to adapt to high-frequency signals, but also required tohave high adhesion to conductor, low thermal expansion coefficient, highglass transition temperature, high flame retardancy, and the like due tothe demands for an increase in the density, high reliability, andadaptability to consideration of the environment.

For example, the adhesion to conductor is desired to be 0.58 kN/m ormore, and further 0.6 kN/m or more, in terms of a copper foil peelstrength as measured using a low profile copper foil (Rz: 1 to 2 μm)having a very small surface roughness on the side to be bonded to resin.

Further, the substrate material for printed wiring board used in theapplication of network related devices, such as a server and a router,is needed to be stacked into the increased number of layers as thedensity of the wiring board is increased, and therefore the substratematerial is required to have high reflow heat resistance andthrough-hole reliability. The glass transition temperature of thematerial as a yardstick for the above properties is desirably 200° C. orhigher, and the thermal expansion coefficient (in the Z-direction at theTg or lower) is desirably 45 ppm/° C. or less, further desirably 43ppm/° C. or less. For achieving low thermal expansion property, theincorporation of an inorganic filler into the resin composition iseffective; however, in a multilayer printed wiring board with theincreased number of layers, for surely obtaining the flow properties ofthe resin for circuit packing, the amount of the inorganic filler to beincorporated is restricted. Therefore, it is desired that even when theamount of the inorganic filler incorporated is relatively small, theresultant resin composition is desired to secure the above-mentionedrequired values.

With respect to high frequency properties, excellent dielectricproperties in a higher frequency range are desired, and a substratematerial using an ordinary E glass substrate is desired to have adielectric constant of 3.8 or less, more desirably 3.7 or less, and evenmore desirably 3.6 or less, and to have an dielectric dissipation factorof 0.007 or less, more desirably 0.006 or less. Furthermore, a substratematerial generally tends to have an increased dielectric dissipationfactor at a higher frequency, but is increasingly strongly needed tosatisfy the above-mentioned required values in a 10 GHz or more bandwhich is a frequency band higher than the conventional 1 to 5 GHz bandfor the dielectric properties values.

For securing flame retardancy, in general, a halogen element-containingflame retardant, especially a bromine-based flame retardant has beenused. However, from the viewpoint of recent global environmentconservation and aggravation prevention, a technique for flameretardation not using a halogen element (especially chlorine atom,bromine atom) that has a risk of generation of dioxins, benzofuran orthe like has become desired.

CITATION LIST Patent Literature

PTL 1: JP 58-069046 A

PTL 2: JP 61-018937 B

PTL 3: JP 2008-95061 A

SUMMARY OF INVENTION Technical Problem

In consideration of the current situation as above, an object of thepresent invention is to provide a thermosetting resin composition havingespecially excellent compatibility and having good dielectric propertiesin a high frequency range (low dielectric constant and low dielectricdissipation factor), high adhesion to conductor, excellent heatresistance, high glass transition temperature, low thermal expansioncoefficient, and high flame retardancy, and to provide a prepreg, alaminate, and a multilayer printed wiring board using the resincomposition.

Solution to Problem

The present inventors have conducted extensive and intensive studieswith a view toward solving the above-mentioned problems. As a result,the inventors have found that a prepreg and a laminate using athermosetting resin composition that contains a polyphenylene etherderivative having a specific molecular structure, a specificthermosetting resin and a phosphorus flame retardant can expressexcellent high frequency properties, high heat resistance, high adhesionto conductors, high glass transition temperature, low thermal expansioncoefficient and high flame retardancy, and have completed the presentinvention.

That is, the present invention relates to the following [1] to [14].

-   [1] A thermosetting resin composition containing:

(A) a polyphenylene ether derivative having an N-substituted maleimidestructure-containing group and a structural unit represented by thefollowing general formula (I) in one molecule,

(B) at least one thermosetting resin selected from the group consistingof an epoxy resin, a cyanate resin and a maleimide compound, and

(C) a phosphorus flame retardant:

wherein R¹ each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, and x represents aninteger of 0 to 4.

-   [2] The thermosetting resin composition according to the above [1],    wherein the N-substituted maleimide structure-containing group is a    group represented by the following general formula (Z):

wherein R² each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, y represents an integerof 0 to 4, and A¹ represents a group represented by the followinggeneral formula (II), (III), (IV) or (V):

wherein R³ each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, and p represents aninteger of 0 to 4:

wherein R⁴ and R⁵ each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or a halogen atom, A² represents analkylene group having 1 to 5 carbon atoms, an alkylidene group having 2to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, acarbonyloxy group, a keto group, a single bond, or a group representedby the following general formula (III-1), and q and r each independentlyrepresent an integer of 0 to 4:

wherein R⁶ and R⁷ each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or a halogen atom, A³ represents analkylene group having 1 to 5 carbon atoms, an isopropylidene group, anether group, a sulfide group, a sulfonyl group, a carbonyloxy group, aketo group or a single bond, and s and t each independently represent aninteger of 0 to 4:

wherein n represents an integer of 0 to 10:

wherein R⁸ and R⁹ each independently represent a hydrogen atom, or analiphatic hydrocarbon group having 1 to 5 carbon atoms, and u representsan integer of 1 to 8.

-   [3] The thermosetting resin composition according to the above [1]    or [2], wherein the structural unit represented by the general    formula (I) is a structural unit represented by the following    formula (I′):

-   [4] The thermosetting resin composition according to the above [2]    or [3], wherein A¹ in the general formula (Z) is a group represented    by any of the following formulae:

-   [5] The thermosetting resin composition according to any one of the    above [1] to [4], wherein the phosphorus flame retardant (C) is at    least one selected from an aromatic phosphate, and a metal salt of a    disubstituted phosphinic acid.-   [6] The thermosetting resin composition according to the above [5],    wherein the aromatic phosphate is represented by the following    general formula (C-1) or (C-2), and the metal salt of a    disubstituted phosphinic acid is represented by the following    general formula (C-3):

wherein R^(C1) to R^(C5) each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, or a halogen atom, A^(c)represents an alkylene group having 1 to 5 carbon atoms, an alkylidenegroup having 2 to 5 carbon atoms, an ether group, a sulfide group, asulfonyl group, a carbonyloxy group, a keto group, or a single bond, eand f each independently represent an integer of 0 to 5, g, h and i eachindependently represent an integer of 0 to 4,

R^(C6) and R^(C7) each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or an aromatic hydrocarbon grouphaving 6 to 14 carbon atoms, M represents a lithium atom, a sodium atom,a potassium atom, a calcium atom, a magnesium atom, an aluminum atom, atitanium atom or a zinc atom, and m1 represents an integer of 1 to 4.

-   [7] The thermosetting resin composition according to any one of the    above [1] to [6], wherein the maleimide compound as the    component (B) is a polymaleimide compound (a) having at least two    N-substituted maleimide groups in one molecule, or a    polyaminobismaleimide compound (c) represented by the following    general formula (VI):

wherein A⁴ has the same definition as that of A¹ in the general formula(Z), and A⁵ represents a group represented by the following generalformula (VII):

wherein R¹⁷ and R¹⁸ each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1to 5 carbon atoms, a hydroxyl group or a halogen atom, A⁸ represents analkylene group having 1 to 5 carbon atoms, an alkylidene group having 2to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, acarbonyloxy group, a keto group, a fluorenylene group, a single bond, ora group represented by the following general formula (VII-1) or (VII-2),and q′ and r′ each independently represent an integer of 0 to 4:

wherein R¹⁹ and R²⁰ each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, or a halogen atom, A⁹represents an alkylene group having 1 to 5 carbon atoms, anisopropylidene group, an m-phenylenediisopropylidene group, ap-phenylenediisopropylidene group, an ether group, a sulfide group, asulfonyl group, a carbonyloxy group, a keto group or a single bond, ands′ and t′ each independently represent an integer of 0 to 4:

wherein R²¹ represents an aliphatic hydrocarbon group having 1 to 5carbon atoms, or a halogen atom, A¹⁰ and A¹¹ each independentlyrepresent an alkylene group having 1 to 5 carbon atoms, anisopropylidene group, an ether group, a sulfide group, a sulfonyl group,a carbonyloxy group, a keto group, or a single bond, and w represents aninteger of 0 to 4.

-   [8] The thermosetting resin composition according to any one of the    above [1] to [7], wherein the content ratio of the component (A) to    the component (B) [(A)/(B)] is from 5/95 to 80/20 by mass.-   [9] The thermosetting resin composition according to any one of the    above [1] to [8], further containing an inorganic filler (D).-   [10] The thermosetting resin composition according to any one of the    above [1] to [9], further containing a curing accelerator (E).-   [11] The thermosetting resin composition according to any one of the    above [1] to [10], further containing an organic solvent.-   [12] A prepreg including the thermosetting resin composition of any    one of the above [1] to [11] and a sheet-form fiber reinforced    substrate.-   [13] A laminate including the prepreg of the above [12] and a metal    foil.-   [14] A multilayer printed wiring board including the prepreg of the    above [12] or the laminate of the above [13].

Advantageous Effects of Invention

The thermosetting resin composition of the present invention hasparticularly good compatibility, excellent high frequency properties(low dielectric constant, low dielectric dissipation factor), highadhesion to conductor, excellent heat resistance, high glass transitiontemperature, low thermal expansion coefficient and high flameretardancy. Accordingly, the prepreg and the laminate to be obtainedusing the thermosetting resin composition can be favorably used forelectronic parts such as multilayer printed wiring boards, etc.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention are described in detailhereinunder.

[Thermosetting Resin Composition]

One aspect of the present invention is a thermosetting resin compositioncontaining:

(A) a polyphenylene ether derivative having an N-substituted maleimidestructure-containing group and a structural unit represented by thefollowing general formula (I) in one molecule [hereinafter this may besimply abbreviated as polyphenylene ether derivative (A) or component(A)],

(B) at least one thermosetting resin selected from the group consistingof an epoxy resin, a cyanate resin and a maleimide compound [hereinafterthis may be simply abbreviated as thermosetting resin (B) or component(B)], and

(C) a phosphorus flame retardant [hereinafter this may be abbreviated ascomponent (C)]:

wherein R¹ each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, and x represents aninteger of 0 to 4.

The components are described in order.

(Polyphenylene Ether Derivative (A))

The polyphenylene ether derivative (A) has an N-substituted maleimidestructure-containing group and a structural unit represented by theabove-mentioned general formula (I) in one molecule. In particular,since the polyphenylene ether derivative (A) has at least oneN-substituted maleimide structure-containing group in one molecule, thethermosetting resin composition can have excellent high frequencyproperties (low dielectric constant, low dielectric dissipation factor),high adhesion to conductor, excellent heat resistance, high glasstransition temperature, low thermal expansion coefficient and high flameretardancy. Here, the thermal expansion coefficient as referred to inthe present invention means a value also called a linear expansioncoefficient.

R¹ in the general formula (I) each independently represents an aliphatichydrocarbon group having 1 to 5 carbon atoms, or a halogen atom.Examples of the aliphatic hydrocarbon group include a methyl group, anethyl group, an n-propyl group, an isopropyl group, an n-butyl group, anisobutyl group, a t-butyl group, an n-pentyl group, etc. The aliphatichydrocarbon group may be an aliphatic hydrocarbon group having 1 to 3carbon atoms, and may be a methyl group. Examples of the halogen atominclude a fluorine atom, a chlorine atom, a bromine atom, an iodineatom, etc. From the viewpoint of halogen-freeness, the halogen atom maybe a fluorine atom.

Among the above, R¹ may be an aliphatic hydrocarbon group having 1 to 5carbon atoms.

x is an integer of 0 to 4, and may be an integer of 0 to 2, and may be2. When x is 1 or 2, R¹ may be substituted at the ortho-position on thebenzene ring (based on the substitution position of the oxygen atom).When x is 2 or more, plural R¹'s may be the same or different.

Specifically, the structural unit represented by the general formula (I)may be a structural formula represented by the following general formula(I′).

The N-substituted maleimide structure-containing group that thepolyphenylene ether derivative (A) has may be, from the viewpoint ofhigh frequency properties (low dielectric constant, low dielectricdissipation factor), adhesion to conductor, heat resistance, glasstransition temperature, thermal expansion coefficient and flameretardancy, a group containing a bismaleimide structure in which thenitrogen atoms of the two maleimide groups bond to each other via anorganic group, and may be a group represented by the following generalformula (Z):

wherein R² each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, y represents an integerof 0 to 4, and A¹ represents a group represented by the followinggeneral formula (II), (III), (IV) or (V).

The aliphatic hydrocarbon group having 1 to 5 carbon atoms and thehalogen atom that R² represents may be described in the same manner asthat for the case of R¹.

y is an integer of 0 to 4, and may be an integer of 0 to 2, and may be0. When y is an integer of 2 or more, plural R²'s may be the same ordifferent.

The group represented by the general formula (II), (III), (IV) or (V)that A¹ represents is as follows:

wherein R³ each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, and p represents aninteger of 0 to 4.

The aliphatic hydrocarbon group having 1 to 5 carbon atoms and thehalogen atom that R³ represents may be described in the same manner asthat for the case of R¹.

p is an integer of 0 to 4, and, from the viewpoint of easy availability,may be an integer of 0 to 2, or 0 or 1, or 0. When p is an integer of 2or more, plural R³'s may be the same or different:

wherein R⁴ and R⁵ each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or a halogen atom, A² represents analkylene group having 1 to 5 carbon atoms, an alkylidene group having 2to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, acarbonyloxy group, a keto group, a single bond, or a group representedby the following general formula (III-1), and q and r each independentlyrepresent an integer of 0 to 4.

The aliphatic hydrocarbon group having 1 to 5 carbon atoms and thehalogen atom that R⁴ and R⁵ represent include the same ones as those forR¹. The aliphatic hydrocarbon group may be an aliphatic hydrocarbongroup having 1 to 3 carbon atoms, and may be a methyl group or an ethylgroup, and may be an ethyl group.

Examples of the alkylene group having 1 to 5 carbon atoms that A²represents include a methylene group, a 1,2-dimethylene group, a1,3-trimethylene group, a 1,4-tetramethylene group, a 1,5-pentamethylenegroup, etc. The alkylene group may be, from the viewpoint of highfrequency properties (low dielectric constant, low dielectricdissipation factor), adhesion to conductor, heat resistance, glasstransition temperature, thermal expansion coefficient and flameretardancy, an alkylene group having 1 to 3 carbon atoms, or may be amethylene group.

Examples of the alkylidene group having 2 to 5 carbon atoms that A²represents include an ethylidene group, a propylidene group, anisopropylidene group, a butylidene group, an isobutylidene group, apentylidene group, an isopentylidene group, etc. Among these, from theviewpoint of high frequency properties (low dielectric constant, lowdielectric dissipation factor), adhesion to conductor, heat resistance,glass transition temperature, thermal expansion coefficient and flameretardancy, it may be an isopropylidene group.

Among the above-mentioned choices, A² may be an alkylene group having 1to 5 carbon atoms or an alkylidene group having 2 to 5 carbon atoms.

q and r each are independently an integer of 0 to 4, and, from theviewpoint of easy availability, may be an integer of 0 to 2, or 0 or 2.When q or r is an integer of 2 or more, plural R⁴'s or plural R⁵'s eachmay be the same or different.

The group represented by the general formula (III-1) that A² representsis as follows:

wherein R⁶ and R⁷ each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or a halogen atom, A³ represents analkylene group having 1 to 5 carbon atoms, an isopropylidene group, anether group, a sulfide group, a sulfonyl group, a carbonyloxy group, aketo group or a single bond, and s and t each independently represent aninteger of 0 to 4.

The aliphatic hydrocarbon group having 1 to 5 carbon atoms and thehalogen atom that R⁶ and R⁷ represent may be described in the samemanner as that for the case of R⁴ and R⁵.

The alkylene group having 1 to 5 carbon atoms that A³ represents includethe same ones as the alkylene group having 1 to 5 carbon atoms that A²represents.

From among the above-mentioned choices, the alkylidene group having 2 to5 carbon atoms may be selected for A³.

s and t each are independently an integer of 0 to 4, and, from theviewpoint of easy availability, may be an integer of 0 to 2, or may be 0or 1, or may be 0. When s or t is an integer of 2 or more, plural R⁶'sor plural R⁷'s each may be the same or different.

In the formula, n represents an integer of 0 to 10.

From the viewpoint of easy availability, n may be an integer of 0 to 5,or may be an integer of 0 to 3.

In the formula, R⁸ and R⁹ each independently represent a hydrogen atom,or an aliphatic hydrocarbon group having 1 to 5 carbon atoms, and urepresents an integer of 1 to 8.

The aliphatic hydrocarbon group having 1 to 5 carbon atoms and thehalogen atom that R⁸ and R⁹ represent may be described in the samemanner as that for the case of R¹.

u is an integer of 1 to 8, and may be an integer of 1 to 3, or may be 1.

A¹ in the group represented by the general formula (Z) may be, from theviewpoint of high frequency properties (low dielectric constant, lowdielectric dissipation factor), adhesion to conductor, heat resistance,glass transition temperature, thermal expansion coefficient and flameretardancy, a group represented by any of the following formulae.

The polyphenylene ether derivative (A) may be a polyphenylene etherderivative represented by the following general formula (A′).

In the formula, A¹, R¹, R², x and y are as defined hereinabove, and mrepresents an integer of 1 or more.

m may be an integer of 1 to 300, or may be an integer of 10 to 300, ormay be an integer of 30 to 200, or may be an integer of 50 to 150.

The polyphenylene ether derivative (A) may be a polyphenylene etherderivative represented by any of the following formulae.

In the formulae, m is the same as m in the general formula (A′).

From the viewpoint of inexpensive raw materials, the derivative may be apolyphenylene ether derivative of the above formula (A′-1), from theviewpoint of excellent dielectric properties and low waterabsorbability, it may be a polyphenylene ether derivative represented bythe formula (A′-2), and from the viewpoint of excellent adhesion toconductor and mechanical properties (elongation, strength at break,etc.), it may be a polyphenylene ether derivative represented by theformula (A′-3). Accordingly, in conformity to the intended properties,one alone or two or more of the polyphenylene ether derivatives of theformulae (A′-1) to (A′-3) may be used either singly or as combined.

The number average molecular weight of the polyphenylene etherderivative (A) of the present invention may be 5,000 to 12,000, or maybe 7,000 to 12,000, or may be 7,000 to 10,000. When the number averagemolecular weight is 5,000 or more, the thermosetting resin compositionof the present invention and the prepreg and the laminate using thecomposition tend to have a more favorable glass transition temperature.When the number average molecular weight is 12,000 or less, thethermosetting resin composition of the present invention tends to bereadily molded into a laminate with better formability.

In this description, the number average molecular weight is a valuecalculated based on the calibration curve drawn using a standardpolystyrene, according to gel permeation chromatography (GPC), and moreprecisely, a value measured according to the number average molecularweight measurement method described in the section of Examples.

(Method for Producing Polyphenylene Ether Derivative (A))

The polyphenylene ether derivative (A) may be obtained, for example,according to the production method mentioned below.

First, an aminophenol compound represented by the following generalformula (VIII) [hereinafter referred to as aminophenol compound (VIII)]is reacted with a polyphenylene ether having, for example, a numberaverage molecular weight of 15,000 to 25,000 in an organic solvent in amode of known redistribution reaction, as associated with reduction inthe molecular weight of the polyphenylene ether, to thereby produce apolyphenylene ether compound having a primary amino group in onemolecule (A″) (hereinafter this may be simply referred to aspolyphenylene ether compound (A″)), and then the polyphenylene ethercompound (A″) is reacted with a bismaleimide compound represented by thegeneral formula (IX) [hereinafter referred to as bismaleimide compound(IX)] in a mode of Michael addition reaction to produce thepolyphenylene ether derivative (A).

In the formula, R² and y are the same as those in the general formula(I).

In the formula, A¹ is the same as in the general formula (I).

Examples of the aminophenol compound (VIII) include o-aminophenol,m-aminophenol, p-aminophenol, etc. Among these, from the viewpoint ofthe reaction yield in producing the polyphenylene ether compound (A″),as well as the heat resistance in producing resin composition, prepregand laminate, the compound may be m-aminophenol or p-aminophenol, or maybe p-aminophenol.

The molecular weight of the polyphenylene ether compound (A″) may becontrolled by the amount to be used of the aminophenol compound (VIII),and when the amount of the aminophenol compound (VIII) used is larger,the molecular weight of the polyphenylene ether (A″) is lower. Namely,the amount to be used of the aminophenol compound (VIII) may beadequately controlled so that the number average molecular weight of thepolyphenylene ether derivative (A) to be produced finally could fallwithin a preferred range.

The amount to be incorporated of the aminophenol compound (VIII) is notspecifically limited, but for example, when the number average molecularweight of the polyphenylene ether to be reacted with the aminophenolcompound (VIII) is 15,000 to 25,000, the amount may fall within a rangeof 0.5 to 6 parts by mass relative to 100 parts by mass of thepolyphenylene ether to give a polyphenylene ether derivative (A) havinga number average molecular weight of 5,000 to 12,000.

Examples of the organic solvent for use in the production step for thepolyphenylene ether compound (A″) include, though not specificallylimited thereto, alcohols such as methanol, ethanol, butanol, butylcellosolve, ethylene glycol monomethyl ether, propylene glycolmonomethyl ether, etc.; ketones such as acetone, methyl ethyl ketone,methyl isobutyl ketone, cyclohexanone, etc.; aromatic hydrocarbons suchas toluene, xylene, mesitylene, etc.; esters such as methoxyethylacetate, ethoxyethyl acetate, butoxyethyl acetate, ethyl acetate, etc.;nitrogen-containing compounds such as N,N-dimethylformamide,N,N-dimethylacetamide, N-methyl-2-pyrrolidone, etc. One alone or two ormore kinds of these may be used either singly or as combined. Amongthese, from the viewpoint of solubility, toluene, xylene and mesitylenemay be used.

In the production step for the polyphenylene ether compound (A″), areaction catalyst may be used as needed. To the reaction catalyst, forexample, the reaction catalyst in known redistribution reaction isapplicable. For example, from the viewpoint of producing thepolyphenylene ether compound (A″) having a stable number averagemolecular weight with good reproducibility, an organic peroxide such ast-butylperoxyisopropyl monocarbonate or the like and a metal carboxylatesuch as manganese naphthenate or the like may be used as combined. Theamount of the reaction catalyst to be used is not specifically limited.For example, from the viewpoint of the reaction speed and antigelationin producing the polyphenylene ether compound (A″), for example, theamount of the organic peroxide may be 0.5 to 5 parts by mass and that ofthe metal carboxylate may be 0.05 to 0.5 parts by mass relative to 100parts by mass of the polyphenylene ether to be reacted with theaminophenol compound (VIII).

The aminophenol compound (VIII), the polyphenylene ether having a numberaverage molecular weight of 15,000 to 25,000, an organic solvent andoptionally a reaction catalyst are put in a reactor each in apredetermined amount, and reacted with heating, keeping the heat andstirring to give the polyphenylene ether compound (A″). For the reactiontemperature and the reaction time in this step, the reaction conditionsin known redistribution reaction are applicable.

From the viewpoint of operability and antigelation, and from theviewpoint of controlling the molecular weight of the polyphenylene ethercompound (A″) for obtaining the component (A) having a desired numberaverage molecular weight, for example, the reaction may be carried outat a reaction temperature of 70 to 110° C. and for a reaction time of 1to 8 hours.

A solution of the polyphenylene ether compound (A″) thus produced in themanner as above may be continuously and directly fed to the next step ofproducing the polyphenylene ether derivative (A). In this stage, thesolution of the polyphenylene ether compound (A″) may be cooled, or maybe controlled to be at the reaction temperature in the next step. Asneeded, the solution may be concentrated to remove a part of the organicsolvent, or may be diluted by adding an organic solvent thereto, asdescribed below.

Examples of the bismaleimide compound (IX) to be used in producing thepolyphenylene ether derivative (A) includebis(4-maleimidophenyl)methane, polyphenylmethanemaleimide,bis(4-maleimidophenyl) ether, bis(4-maleimidophenyl) sulfone,3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide,4-methyl-1,3-phenylenebismaleimide, m-phenylenebismaleimide,2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl) sulfide, bis(4-maleimidophenyl) ketone,2,2-bis(4-(4-maleimidophenoxy)phenyl)propane,bis(4-(4-maleimidophenoxy)phenyl) sulfone,4,4′-bis(3-maleimidophenoxy)biphenyl, and1,6-bismaleimido-(2,2,4-trimethyl)hexane. These may be used individuallyor in combination.

Of these, bis(4-maleimidophenyl)methane,3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide, and2,2-bis(4-(4-maleimidophenoxy)phenyl)propane may be selected.

Bis(4-maleimidophenyl)methane may be used because the polyphenyleneether derivative containing the formula (A′-1) above is obtained and itis inexpensive.

3,3′-Dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide may be usedbecause the polyphenylene ether derivative containing the formula (A′-2)above is obtained and exhibits excellent dielectric properties and lowwater absorption properties.

2,2-Bis(4-(4-maleimidophenoxy)phenyl)propane may be used because thepolyphenylene ether derivative containing the formula (A′-3) above isobtained and exhibits high adhesion to conductor and excellentmechanical properties (elongation, strength at break).

The amount of the bismaleimide compound (IX) is determined according tothe amount of the aminophenol compound (VIII) used. Specifically, thebismaleimide compound may be incorporated so that the equivalent ratio(Tb1/Ta1) of the maleimide group equivalent (Tb1) of the bismaleimidecompound (IX) to the —NH₂ group equivalent (Ta1) of the aminophenolcompound (VIII) could be in the range of 2 to 6, or in a rage of 2 to 4.When the bismaleimide compound is used in the equivalent ratio range asabove, the thermosetting resin composition, the prepreg and the laminateof the present invention tend to have more excellent heat resistance,high glass transition temperature and high flame retardancy.

In the Michael addition reaction conducted when producing thepolyphenylene ether derivative (A), a reaction catalyst may be used asneeded. With respect to the reaction catalyst used, there is noparticular limitation. However, examples of the reaction catalystinclude acidic catalysts, such as p-toluenesulfonic acid; amines, suchas triethylamine, pyridine, and tributylamine; imidazole compounds, suchas methylimidazole and phenylimidazole; and phosphorus catalysts, suchas triphenylphosphine. These may be used individually or in combination.With respect to the amount of the reaction catalyst incorporated, thereis no particular limitation. However, for example, relative to 100 partsby mass of the polyphenylene ether compound (A″), the reaction catalystcan be used in an amount in the range of 0.01 to 5 parts by mass.

The bismaleimide compound (IX) and optionally a reaction catalyst andothers are put into the solution of the polyphenylene ether compound(A″) solution each in a predetermined amount, and reacted with heating,keeping the heat and stirring in a mode of Michael reaction to give thepolyphenylene ether derivative (A). Regarding the reaction conditions inthis step, for example, from the viewpoint of operability andantigelation, the reaction temperature may be 50 to 160° C., and thereaction time may be 1 to 10 hours. In addition, in this step, anorganic solvent may be added, or the reaction system may be concentratedas mentioned above, to thereby control the reaction concentration (solidconcentration), and the solution viscosity. For the additional organicsolvent, the organic solvents exemplified in the section of theproduction step for the polyphenylene ether compound (A″) areapplicable, and one alone or two or more kinds of these may be usedeither singly or as combined. Among these, from the viewpoint ofsolubility, methyl ethyl ketone, cyclohexanone, propylene glycolmonomethyl ether, N,N-dimethylformamide and N,N-dimethylacetamide may beselected.

The reaction concentration (solid concentration) in the production stepfor the polyphenylene ether derivative (A) and the polyphenylene ethercompound (A″) is not specifically limited, but, for example, in eachproduction step, the concentration may be 10 to 60% by mass, and may be20 to 50% by mass. When the reaction concentration is 10% by mass ormore, the reaction speed is not too low, and tends to be favorable fromthe viewpoint of production cost. When the reaction concentration is 60%by mass or less, better solubility tends to be attained. If so, inaddition, the solution viscosity may be low and the stirring efficiencytends to be good to suppress gelation.

After production of the polyphenylene ether derivative (A), a part orall of the organic solvent may be optionally removed from the solutionfor concentration, or an additional organic solvent may be added theretofor dilution, in accordance with the operability in taking out thederivative from the reactor or with the use condition (for example,solution viscosity or solution concentration suitable for production ofprepreg) in preparing the thermosetting resin composition of the presentinvention by adding various thermosetting resins to the polyphenyleneether derivative (A). The additional organic solvent is not specificallylimited, and one or more organic solvents mentioned above may be used.

The formation of the polyphenylene ether compound (A″) and thepolyphenylene ether derivative (A) in the above-mentioned productionsteps may be confirmed through GPC and IR analysis by sampling a smallamount of the product after each step.

First, with respect to the polyphenylene ether compound (A″), theproduction of a desired polyphenylene ether compound (A″) can beconfirmed by GPC showing that the molecular weight is reduced to belower than the polyphenylene ether having a number average molecularweight of 15,000 to 25,000 and that the peak of the aminophenol compound(VIII) as a raw material has disappeared, and by IR analysis showingthat a peak of the primary amino group appears at 3,300 to 3,500 cm⁻¹.With respect to the polyphenylene ether derivative (A) which has beenpurified by reprecipitation, the production of a desired polyphenyleneether derivative (A) can be confirmed by IR analysis showing that thepeak of the primary amino group at 3,300 to 3,500 cm⁻¹ has disappearedand that a peak of the carbonyl group of maleimide appears at 1,700 to1,730 cm⁻¹.

The thermosetting resin composition of the present invention tends to bemore excellent in adhesion to conductor, heat resistance, thermalexpansion coefficient, flame retardancy and workability (in drilling,cutting) than the resin composition containing the polyphenylene ethercompound (A″) and the component (B) to be mentioned below.

(Thermosetting Resin (B))

The resin component (B) contained in the thermosetting resin compositionof the present invention is at least one thermosetting resin selectedfrom the group consisting of an epoxy resin, a cyanate resin and amaleimide compound. The maleimide compound does not include theabove-mentioned polyphenylene ether derivative (A).

The epoxy resin may be an epoxy resin having two or more epoxy groups inone molecule. Here, the epoxy resin is grouped into a glycidylether-type epoxy resin, a glycidylamine-type epoxy resin, a glycidylester-type epoxy resin, etc. Among these, a glycidyl ether-type epoxyresin may be selected.

The epoxy resin is grouped into various types of epoxy resins dependingon the difference in the main skeleton, and various types of the epoxyresins mentioned above may be further grouped into a bisphenol-typeepoxy resin such as a bisphenol A-type epoxy resin, a bisphenol F-typeepoxy resin, a bisphenol S-type epoxy resin, etc.; an alicyclic epoxyresin; an aliphatic linear epoxy resin; a novolak-type epoxy resin suchas a phenol-novolak-type epoxy resin, a cresol-novolak-type epoxy resin,a bisphenol A-novolak-type epoxy resin, a bisphenol F-novolak-type epoxyresin, etc.; a phenol-aralkyl-type epoxy resin, a stilbene-type epoxyresin, a dicyclopentadiene-type epoxy resin, a naphthaleneskeleton-containing epoxy resin such as a naphthol-novolak-type epoxyresin, a naphthol-aralkyl-type epoxy resin, etc.; a biphenyl-type epoxyresin, a biphenylaralkyl-type epoxy resin; a xylylene-type epoxy resin;a dihydroanthracene-type epoxy resin; a dicyclopentadiene-type epoxyresin, etc.

One alone or two or more kinds of epoxy resins may be used either singlyor as combined. Among these, from the viewpoint of high frequencyproperties, heat resistance, glass transition temperature, thermalexpansion coefficient and flame retardancy, a naphthaleneskeleton-containing epoxy resin and a biphenylaralkyl-type epoxy resinmay be used.

In the case where an epoxy resin is used as the component (B), ifdesired, a curing agent or a curing aid for epoxy resin may be used ascombined. Examples of these include, though not specifically limitedthereto, polyamine compounds such as diethylenetriamine,triethylenetetramine, diaminodiphenylmethane, m-phenylenediamine,dicyandiamide, etc.; polyphenol compounds such as bisphenol A,phenol-novolak resin, cresol-novolak resin, bisphenol A-novolak resin,phenolaralkyl resin, etc.; acid anhydrides such as phthalic anhydride,pyromellitic anhydride, etc.; carboxylic acid compounds; active estercompounds, etc. One alone or two or more of these may be used eithersingly or as combined. The amount thereof to be used is not specificallylimited and may be adequately controlled depending on the object. Amongthese, from the viewpoint of heat resistance, glass transitiontemperature, thermal expansion coefficient, storage stability andinsulation reliability, polyphenol compounds and active ester compoundsmay be used.

Examples of the cyanate resin include, though not specifically limitedthereto, 2,2-bis(4-cyanatophenyl)propane, bis(4-cyanatophenyl)ethane,bis(3,5-dimethyl-4-cyanatophenyl)methane,2,2-bis(4-cyanatophenyl)-1,1,1,3,3,3-hexafluoropropane,α,α′-bis(4-cyanatophenyl)-m-diisopropylbenzene, cyanate ester compoundof phenol-added dicyclopentadiene polymer, phenol-novolak-type cyanateester compound and cresol-novolak-type cyanate ester compound. One aloneor two or more kinds of cyanate resins may be used either singly or ascombined. Among these, from the viewpoint of production cost as well asfrom the viewpoint of total balance of high frequency properties andother properties, 2,2-bis(4-cyanatophenyl)propane may be used.

In the case where a cyanate resin is used as the component (B), ifdesired, a curing agent or a curing aid for cyanate resin may be used ascombined. Examples of these include, though not specifically limitedthereto, monophenol compounds, polyphenol compounds, amine compounds,alcohol compounds, acid anhydrides, carboxylic acid compounds, etc. Onealone or two or more of these may be used either singly or as combined.The amount of the curing agent and the curing aid to be used is notspecifically limited and may be adequately controlled depending on theobject. Among these, from the viewpoint of high frequency properties,heat resistance, moisture absorption resistance and storage stability,monophenol compounds may be used.

In the case where a cyanate resin is used as combined with a monophenolcompound, from the viewpoint of solubility in organic solvent, a methodof pre-reacting them to give a phenol-modified cyanate prepolymer may beemployed. Regarding the monophenol compound to be used in combination,all the prescribed amount thereof may be incorporated inprepolymerization, or the prescribed amount may be divided in portionsand added portionwise before and after prepolymerization, but from theviewpoint of storage stability, the method of portionwise incorporatingthe compound may be employed.

The maleimide compound is not specifically limited, but, for example, atleast one of (a) a polymaleimide compound having at least twoN-substituted maleimide group in one molecule [hereinafter this may bereferred to as component (a)] and (c) a polyaminobismaleimide compoundrepresented by the following general formula (VI) (hereinafter this maybe referred to as component (c)] may be contained. From the viewpoint ofsolubility in organic solvent, high frequency properties, adhesion toconductor and prepreg formability, the maleimide compound may be thepolyaminobismaleimide compound (c).

The polyaminobismaleimide compound (c) may be obtained, for example, byreacting the component (a) and an aromatic diamine compound (b) havingtwo primary amino groups in one molecule [hereinafter this may bereferred to as component (b)] in a mode of Michael addition reaction inan organic solvent.

In the formula, A⁴ has the same definition as A¹ in the above generalformula (Z), A⁵ is a group represented by the following general formula(VII).

In the formula, R¹⁷ and R¹⁸ each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1to 5 carbon atoms, a hydroxyl group or a halogen atom, A⁸ represents analkylene group having 1 to 5 carbon atoms, an alkylidene group having 2to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, acarbonyloxy group, a keto group, a fluorenylene group, a single bond, ora group represented by the following general formula (VII-1) or (VII-2),and q′ and r′ each independently represent an integer of 0 to 4.

In the formula, R¹⁹ and R²⁰ each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, or a halogen atom, A⁹represents an alkylene group having 1 to 5 carbon atoms, anisopropylidene group, an m-phenylenediisopropylidene group, ap-phenylenediisopropylidene group, an ether group, a sulfide group, asulfonyl group, a carbonyloxy group, a keto group or a single bond, ands′ and t′ each independently represent an integer of 0 to 4.

In the formula, R²¹ represents an aliphatic hydrocarbon group having 1to 5 carbon atoms, or a halogen atom, A¹⁰ and A¹¹ each independentlyrepresent an alkylene group having 1 to 5 carbon atoms, anisopropylidene group, an ether group, a sulfide group, a sulfonyl group,a carbonyloxy group, a keto group or a single bond, and w represents aninteger of 0 to 4.

The aliphatic hydrocarbon group having 1 to 5 carbon atoms and thehalogen atom that R¹⁷, R¹⁸, R¹⁹, R²⁰ and R²¹ in the above generalformula (VII), (VII-1) or (VII-2) represent include the same ones asthose of R¹ in the general formula (I). The aliphatic hydrocarbon groupmay be an aliphatic hydrocarbon group having 1 to 3 carbon atoms, andmay be a methyl group or an ethyl group.

A⁴ in the general formula (VI) have the same definition as A¹ in thegeneral formula (Z).

The alkylene group having 1 to 5 carbon atoms and the alkylidene grouphaving 2 to 5 carbon atoms that A⁸, A⁹ and A¹⁰ in the above generalformula (VII), (VII-1) or (VII-2) represent may be described in the samemanner as that for the case of A² in the general formula (III). Thealkylene group having 1 to 5 carbon atoms that A¹⁰ and A¹¹ in thegeneral formula (VII-2) represent may be described in the same manner asthat for the case of A² in the general formula (III).

q′ and r′ each are an integer of 0 to 4, and from the viewpoint of easyavailability, both may be an integer of 0 to 2, or may be 0 or 2. s′ andt′ each are an integer of 0 to 4, and from the viewpoint of easyavailability, both may be an integer of 0 to 2, or may be 0 or 1, or maybe 0. w is an integer of 0 to 4, and from the viewpoint of easyavailability, may be an integer of 0 to 2, or may be 0.

The component (a) is not specifically limited, but for example, the sameones as those of the above-mentioned bismaleimide compound (IX) areapplicable. Examples of the component (a) includebis(4-maleimidophenyl)methane, polyphenylmethanemaleimide,bis(4-maleimidophenyl) ether, bis(4-maleimidophenyl) sulfone,3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide,4-methyl-1,3-phenylenebismaleimide, m-phenylenebismaleimide,2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl) sulfide, bis(4-maleimidophenyl) ketone,2,2-bis(4-(4-maleimidophenoxy)phenyl)propane,bis(4-(4-maleimidophenoxy)phenyl) sulfone,4,4′-bis(3-maleimidophenoxy)biphenyl, 1,6-bismaleimido-(2,2,4-trimethyl)hexane, etc. These may be used individually or incombination, depending on the object and use. The component (a) may be abismaleimide compound, and may be bis(4-maleimidophenyl)methane from theviewpoint of inexpensiveness, may be3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethanebismaleimide from theviewpoint of excellent dielectric properties and low water absorption,and may be 2,2-bis(4-(4-maleimidophenoxy)phenyl)propane from theviewpoint of high adhesion to conductor and excellent mechanicalproperties (elongation, strength at break).

As described above, the polyaminobismaleimide compound (c) may beobtained by reacting the above component (a) and an aromatic diaminecompound (b) having two primary amino groups in one molecule in anorganic solvent in a mode of Michael addition reaction.

Examples of the component (b) include, though not specifically limitedthereto, 4,4′-diaminodiphenylmethane,4,4′-diamino-3,3′-dimethyl-diphenylmethane,4,4′-diamino-3,3′-diethyl-diphenylmethane, 4,4′-diaminodiphenyl ether,4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone,4,4′-diaminodiphenyl ketone, 4,4′-diaminobiphenyl,3,3′-dimethyl-4,4′-diaminobiphenyl, 2, 2′-dimethyl-4,4′-diaminobiphenyl,3,3′-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane,3,3-dimethyl-5,5-diethyl-4, 4-diphenylmethanediamine,2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane,1, 3-bis(3-aminophenoxy)benzene, 1, 3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4′-bis(4-aminophenoxy)biphenyl,1,3-bis(1-4-(4-aminophenoxy)phenyl)-1-methylethylkenzene, 1,4-bis(1-4-(4-aminophenoxy)phenyl)-1-methylethylkenzene,4,4′-[1,3-phenylenebis(1-methylethylidene)]bisaniline, 4,4′-[1,4-phenylenebis(1-methylethylidene)]bisaniline,3,3′-[1,3-phenylenebis(1-methylethylidene)]bisaniline,bis(4-(4-aminophenoxy)phenyl) sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, 9,9-bis(4-aminophenyl)fluorene, etc. These components (b) maybe used individually or in combination.

Among these, from the viewpoint of achieving high solubility in anorganic solvent and high reaction rate for the synthesis as well as highheat resistance, the component may be selected from4,4′-diaminodiphenylmethane, 4,4′-diamino-3,3′-dimethyl-diphenylmethane,4,4′-diamino-3,3′-diethyl-diphenylmethane,2,2-bis(4-(4-aminophenoxy)phenyl)propane,4,4′-[1,3-phenylenebis(1-methylethylidene)]bisaniline, and 4,4′-[1,4-phenylenebis(1-methylethylidene)]bisaniline. From the viewpoint of theinexpensiveness in addition to the above-mentioned high solubility, highreaction rate, and high heat resistance, the component may be4,4′-diaminodiphenylmethane, 4,4′-diamino-3,3′-dimethyl-diphenylmethane,or 4,4′-diamino-3,3′-diethyl-diphenylmethane. Further, from theviewpoint of achieving high adhesion to conductor in addition to theabove-mentioned high solubility, high reaction rate, and high heatresistance, the compound may be2,2-bis(4-(4-aminophenoxy)phenyl)propane,4,4′-[1,3-phenylenebis(1-methylethylidene)]bisaniline, or4,4′-[1,4-phenylenebis(1-methylethylidene)]bisaniline. Furthermore, fromthe viewpoint of achieving excellent high-frequency properties andmoisture absorption resistance in addition to the above-mentioned highsolubility, high reaction rate, high heat resistance, and high adhesionto conductor, the component may be selected from4,4′-[1,3-phenylenebis(1-methylethylidene)]bisaniline and4,4′-[1,4-phenylenebis(1-methylethylidene)]bisaniline. According to theobject and use, these may be used individually or in combination.

With respect to the organic solvent used in producing thepolyaminobismaleimide compound (c), there is no particular limitation.However, for example, the organic solvents mentioned above as examplesin connection with the production step for the polyphenylene ethercompound (A″) can be applied. These may be used individually or incombination. Of these, methyl ethyl ketone, cyclohexanone, propyleneglycol monomethyl ether, N, N-dimethylformamide, andN,N-dimethylacetamide may be used from the viewpoint of solubility.

With respect to the amounts of the component (a) and the component (b)used in producing the component (c), the component (a) and the component(b) may be incorporated so that the equivalent ratio (Tb2/Ta2) of themaleimide group equivalent (Tb2) of the component (a) to the —NH₂ groupequivalent (Ta2) of the component (b) could be in the range of 1 to 10,or could be in the range of 2 to 10. When the component (a) andcomponent (b) are used so that the equivalent ratio could be in theabove range, the thermosetting resin composition, the prepreg and thelaminate of the present invention can have excellent high frequencyproperties, high adhesion to conductor, excellent heat resistance, highglass transition temperature and powerful flame retardancy.

A reaction catalyst may not be used for the Michael addition reaction inproducing the polyaminobismaleimide compound (c), but may be used asneeded. The reaction catalyst is not specifically limited, and thereaction catalyst usable in the Michael addition reaction in producingthe above-mentioned polyphenylene ether derivative (A) is applicable.Also as described above, the amount of the reaction catalyst to beincorporated is not specifically limited.

In the case where a maleimide compound is used as the component (B), acuring agent for the maleimide compound, a crosslinking agent, a curingaid and other may be used. These are not specifically limited, andexamples thereof include vinyl compounds such as styrene monomer,divinylbenzene, divinylbiphenyl, etc.; (meth)acrylate compounds; allylcompounds such as triallyl cyanurate, triallyl isocyanurate, etc.;polyamine compounds such as diaminodiphenylmethane, etc. One alone ortwo or more of these may be used either singly or as combined. Theamount of these to be used is not also specifically limited, and may beadequately controlled depending on the object. Among these, from theviewpoint of high frequency properties and heat resistance, vinylcompounds or polyamine compounds may be used.

The above-mentioned component (a) and component (b) and an organicsolvent and optionally a reaction catalyst and others are put into areactor each in a predetermined amount, and with heating, keeping theheat and stirring, these are reacted in a mode of Michael additionreaction to give the polyaminobismaleimide compound (c). For thereaction conditions such as the reaction temperature, the reaction timeand others in this step, for example, the reaction conditions in theMichael addition reaction in producing the above-mentioned polyphenyleneether derivative (A) are applicable.

The reaction concentration (solid concentration) is not specificallylimited, but may be 10 to 90% by mass, and may be 20 to 80% by mass.When the reaction concentration is 10% by mass or more, the reactionspeed is not too low, and tends to be advantageous from the viewpoint ofproduction cost. When the reaction concentration is 90% by mass or less,better solubility tends to be attained. If so, in addition, the solutionviscosity may be low and the stirring efficiency tends to be good tosuppress gelation. After production of the polyaminobismaleimidecompound (c), a part or all of the organic solvent may be removed (forconcentration), or an additional organic solvent may be added fordilution in accordance with the intended object, like in producing thepolyphenylene ether derivative (A).

(Content of Component (A) and Component (B), and Content Ratio Thereof)

The content of the component (A) is not specifically limited, but is,from the viewpoint of high frequency properties, preferably 3% by massor more relative to 100 parts by mass of the sum total of the components(A) to (C), more preferably 5% by mass or more.

The content of the component (B) is not specifically limited, but is,from the viewpoint of high frequency properties and formability,preferably 10 to 90% by mass relative to 100 parts by mass of the sumtotal of the components (A) to (C), more preferably 20 to 80% by mass ormore.

The content ratio of the component (A) to the component (B) [(A)/(B)] isnot specifically limited, and may be 5/95 to 80/20 by mass, may be 5/95to 75/25, may be 5/95 to 70/30, and may be 10/90 to 70/30. When thecontent ratio of the component (A) to the total content of the component(A) and the component (B) is 5% by mass or more, more excellent highfrequency properties and low moisture absorption tend to be attained.When the ratio is 80% by mass or less, more excellent heat resistance,more excellent formability and more excellent workability tend to beattained.

(Phosphorus Flame Retardant (C))

The thermosetting resin composition of the present invention furthercontains a phosphorus flame retardant (C). Using a phosphorus flameretardant (C), the composition enables flame retardancy impartationwhile realizing halogen-freeness, and not limited thereto, and asidefrom that, the phosphorus flame retardant (C) attains excellent highfrequency properties (low dielectric constant, low dielectricdissipation factor), high adhesion to conductor, excellent heatresistance, low thermal expansion coefficient and high glass transitiontemperature.

One alone or two or more kinds of phosphorus flame retardants (C) may beused either singly or as combined.

Not specifically limited, the phosphorus flame retardant (C) may be anyone containing a phosphorus atom among those generally used as a flameretardant, and may be an inorganic phosphorus flame retardant or anorganic phosphorus flame retardant. From the viewpoint of environmentalissues, preferably, the flame retardant does not contain a halogen atom.From the viewpoint of high frequency properties (low dielectricconstant, low dielectric dissipation factor), adhesion to conductor,heat resistance, glass transition temperature, thermal expansioncoefficient and flame retardancy, an organic phosphorus flame retardantmay be used.

Examples of the inorganic phosphorus flame retardant include redphosphorus; ammonium phosphates such as monoammonium phosphate,diammonium phosphate, triammonium phosphate, ammonium polyphosphate,etc.; inorganic nitrogen-containing phosphorus compounds such asphosphoric acid amides, etc.; phosphoric acid; phosphine oxide, etc.

Examples of the organic phosphorus flame retardant include aromaticphosphates, monosubstituted phosphonic diesters, disubstitutedphosphinates, metal salts of disubstituted phosphinic acids, organicnitrogen-containing phosphorus compounds, cyclic organic phosphoruscompounds, etc. Among these, aromatic phosphate compounds, and metalsalts of disubstituted phosphinic acids may be selected. Here, “metalsalts” may be any of lithium salts, sodium salts, potassium salts,calcium salts, magnesium salts, aluminum salts, titanium salts, and zincsalts, or may be aluminum salts. Among the organic phosphorus flameretardants, aromatic phosphates may be selected.

Examples of the aromatic phosphates include triphenyl phosphate,tricresyl phosphate, trixylenyl phosphate, cresyldiphenyl phosphate,cresyl di-2,6-xylenyl phosphate, resorcinol bis(diphenyl phosphate),1,3-phenylenebis(di-2,6-xylenyl phosphate), bisphenol A bis(diphenylphosphate), 1,3-phenylenebis(diphenyl phosphate), etc.

Examples of the monosubstituted phosphonic diesters include divinylphenylphosphonate, diallyl phenylphosphonate, bis(1-butenyl)phenylphosphonate, etc.

Examples of the disubstituted phosphinates include phenyldiphenylphosphinate, methyl diphenylphosphinate, etc.

Metal salts of disubstituted phosphinic acids include metal salts ofdialkylphosphinic acids, metal salts of diallylphosphinic acids, metalsalts of divinylphosphinic acids, metal salts of diarylphosphinic acids,etc. These metal salts may be, as mentioned above, any of lithium salts,sodium salts, potassium salts, calcium salts, magnesium salts, aluminumsalts, titanium salts, and zinc salts, and aluminum salts may beselected.

Examples of the organic nitrogen-containing phosphorus compounds includephosphazene compounds such as bis(2-allylphenoxy)phosphazene,dicresylphosphazene, etc.; melamine compounds such as melaminephosphate, melamine pyrophosphate, melamine polyphosphate, melampolyphosphate, etc.

The cyclic organic phosphorus compounds include9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide,10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide,etc.

The aromatic phosphate may be an aromatic phosphate represented by thefollowing general formula (C-1) or (C-2), and the metal salt of adisubstituted phosphinic acid may be a metal salt of a disubstitutedphosphinic acid represented by the following general formula (C-3).

In the formulae, R^(C1) to R^(C5) each independently represent analiphatic hydrocarbon group having 1 to 5 carbon atoms, or a halogenatom. A^(C) represents an alkylene group having 1 to 5 carbon atoms, analkylidene group having 2 to 5 carbon atoms, an ether group, a sulfidegroup, a sulfonyl group, a carbonyloxy group, a keto group or a singlebond. e and f each independently represent an integer of 0 to 5, g, hand i each independently represent an integer of 0 to 4.

R^(C6) and R^(C7) each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or an aromatic hydrocarbon grouphaving 6 to 14 carbon atoms. M represents a lithium atom, a sodium atom,a potassium atom, a calcium atom, a magnesium atom, an aluminum atom, atitanium atom, or a zinc atom. m1 represents an integer of 1 to 4.

The aliphatic hydrocarbon group having 1 to 5 carbon atoms and thehalogen atom that R^(C1) to R^(C5) represent include the same ones asthose of R¹ in the above-mentioned general formula (I).

The alkylene group having 1 to 5 carbon atoms and the alkylidene grouphaving 2 to 5 carbon atoms that A^(C) represents may be described in thesame manner as that for the case of A². Among the above-mentionedchoices, A^(C) may be an alkylene group having 1 to 5 carbon atoms, analkylidene group having 2 to 5 carbon atoms or a single bond, and may bean isopropylidene group or a single bond.

e and f each may be an integer of 0 to 2, or may be 2. g, h and i eachmay be an integer of 0 to 2, or may be 0 or 1, or may be 0.

The aliphatic hydrocarbon group having 1 to 5 carbon atoms that R^(C6)and R^(C7) represent include the same ones as those of R¹ in the generalformula (I). The aliphatic hydrocarbon group may be an aliphatichydrocarbon group having 1 to 3 carbon atoms, and may be an ethyl group.

Examples of the aromatic hydrocarbon group having 6 to 14 carbon atomsthat R^(C6) and R^(C7) represent include a phenyl group, a naphthylgroup, a biphenylyl group, an anthryl group, etc. The aromatichydrocarbon group may be an aromatic hydrocarbon group having 6 to 10carbon atoms.

m1 represents a valence of a metal ion, that is, it varies within arange of 1 to 4 depending on the kind of M.

M may be an aluminum atom. When M is an aluminum atom, m1 is 3.

(Content of Component (C))

The content ratio of the phosphorus flame retardant (C) in thethermosetting resin composition of the present invention is notspecifically limited, but for example, the content of the phosphorusatom in the solid-equivalent thermosetting resin composition (the sumtotal of the other components than the component (D) to be mentionedbelow) may be 0.2 to 5% by mass, or may be 0.3 to 3% by mass. When thephosphorus atom content is 0.2% by mass or more, better flame retardancytends to be attained. When the phosphorus content is 5% by mass or less,better formability, higher adhesion to conductor, more excellent heatresistance and higher glass transition temperature tends to be attained.

<Other Components>

The thermosetting resin composition of the present invention, ifnecessary, may contain at least one component selected from an inorganicfiller (D) [hereinafter, frequently referred to as “component (D)”] anda curing accelerator (E) [hereinafter, frequently referred to as“component (E)”]. By virtue of containing these components, a laminateobtained using the resultant resin composition can be further improvedin various properties.

For example, an appropriate inorganic filler (D) optionally incorporatedin the thermosetting resin composition of the present invention canimprove low thermal expansion coefficient, high modulus of elasticity,heat resistance and flame retardancy. An appropriate curing accelerator(E) incorporated in the thermosetting resin composition can improve thecurability of the composition and therefore can improve high frequencyproperties, heat resistance, adhesion to conductor, modulus ofelasticity and glass transition temperature.

Further, any other flame retardant than the above-mentioned phosphorusflame retardant (C) and a flame retardant promoter may be used alongwith the component (C).

(Inorganic Filler (D))

The component (D) is not specifically limited, but examples thereofinclude silica, alumina, titanium oxide, mica, beryllia, bariumtitanate, potassium titanate, strontium titanate, calcium titanate,aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminumsilicate, calcium carbonate, calcium silicate, magnesium silicate,silicon nitride, boron nitride, clay (calcined clay, etc.), talc,aluminum borate, aluminum borate, silicon carbide, etc. These may beused individually or in combination. Among these, from the viewpoint ofthermal expansion coefficient, modulus of elasticity, heat resistanceand flame retardancy, the component may be silica, alumina, mica ortalc, or may be silica or alumina, or may be silica. Examples of silicainclude a precipitated silica produced according to a wet method andhaving a high water content, and a dry-method silica produced accordingto a dry method and containing little bound water, and further, thedry-method silica includes ground silica, fumed silica and molten silica(molten spherical silica) as grouped depending on the difference in theproduction method.

With respect to the shape and the particle diameter of the inorganicfiller (D), there is no particular limitation, but, for example, theparticle size may be 0.01 to 20 μm, or may be 0.1 to 10 μm. The term“particle diameter” used here indicates an average particle diameter,which corresponds to a particle diameter determined at a point of 50%volume in a cumulative frequency distribution curve obtained from theparticle diameters when the whole volume of the particles is taken as100%. The particle diameter can be measured by means of a particle sizedistribution measurement apparatus using a laser diffraction scatteringmethod or the like.

In the case where the component (D) is used, the content ratio of thecomponent (D) in the thermosetting resin composition is not specificallylimited, but from the viewpoint of thermal expansion coefficient,modulus of elasticity, heat resistance and flame retardancy, the contentratio of the component (D) in the thermosetting resin composition may be3 to 65% by volume, or may be 5 to 60%, or may be 15 to 55% by volume.When the content ratio of the component (D) in the thermosetting resincomposition falls within the above range, better curability, formabilityand chemical resistance tend to be attained.

In addition, in the case where the component (D) is used, if desired, acoupling agent may be used together with it for the purpose of improvingthe dispersibility of the component (D) and improving the adhesionbetween the component (D) and the organic component in the resincomposition. The coupling agent is not specifically limited, and forexample, a silane coupling agent or a titanate coupling agent may beadequately selected and used. One alone or two or more kinds of couplingagents may be used either singly or as combined. The amount of thecoupling agent to be used is not also specifically limited, and forexample, the amount may be 0.1 to 5 parts by mass relative to 100 partsby mass of the component (D), or may be 0.5 to 3 parts by mass. Withinthe range, various properties can be prevented from degrading and thecharacteristics by the use of the component (D) tend to be effectivelyexhibited.

In the case where a coupling agent is used, a system of using aninorganic filler that has been previously surface-treated in dry or wetwith a coupling agent may be employed, but not a so-called integralblending system where the component (D) is first incorporated in theresin composition and then a coupling agent is added thereto. Employingthe former system promotes effective expression of the characteristicsof the component (D).

In the case where the component (D) is contained, if desired, thecomponent (D) may be previously dispersed in an organic solvent to be aslurry for the purpose of improving the dispersibility of the component(D) in the thermosetting resin composition. The organic solvent to beused in forming the component (D) into a slurry is not specificallylimited, and for example, the organic solvents exemplified hereinabovein the production step for the polyphenylene ether compound (A″) areapplicable. One alone or two or more kinds of these may be used eithersingly or as combined. Among these, from the viewpoint ofdispersibility, methyl ethyl ketone, methyl isobutyl ketone andcyclohexanone may be selected. The solid content (nonvolatile content)concentration of the slurry is not specifically limited, but forexample, from the viewpoint of precipitation and dispersion performanceof the inorganic filler (D), the concentration may be 50 to 80% by mass,or may be 60 to 80% by mass.

(Curing Accelerator (E))

In the case where the component (E) is contained in the thermosettingresin composition of the present invention, a suitable component (E) maybe used in accordance with the kind of the component (B) to be used.

In the case where an epoxy resin is used as the component (B), examplesof the component (E) include imidazole compounds and derivativesthereof; tertiary amine compounds; quaternary ammonium compounds;phosphorus compounds such as triphenyl phosphine, etc. One alone or twoor more kinds of these may be used either singly or as combined. Amongthese, from the viewpoint of heat resistance, glass transitiontemperature and storage stability, imidazole compounds and derivativesthereof or phosphorus compounds may be used. Examples of the imidazolecompounds include methylimidazole, phenylimidazole, isocyanate-maskedimidazole (for example, addition reaction product of hexamethylenediisocyanate resin and 2-ethyl-4-methylimidazole, etc.) and others, andisocyanate-masked imidazole may be selected.

Examples of the component (E) in the case where an isocyanate resin isused as the component (B) include imidazole compounds and derivativesthereof; carboxylates with manganese, cobalt, zinc or the like; organicmetal compounds such as acetylacetone complexes with a transition metalof manganese, cobalt, zinc or the like, etc. One alone or two or morekinds of these may be used either singly or as combined. Among these,from the viewpoint of heat resistance, glass transition temperature andstorage stability, organic metal compounds may be used.

Examples of the component (E) in the case where a maleimide compound isused as the component (B) include acidic catalysts such asp-toluenesulfonic acid, etc.; amine compounds such as triethylamine,pyridine, tributylamine, etc.; imidazole compounds such asmethylimidazole, phenylimidazole, isocyanate-masked imidazole (forexample, addition reaction product of hexamethylene diisocyanate resinand 2-ethyl-4-methylimidazole); tertiary amine compounds; quaternaryammonium compounds; phosphorus compounds such as triphenyl phosphine,etc.; organic peroxides such as dicumyl peroxide,2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3,5-dimethyl-2,5-bis(t-butylperoxy)hexane,t-butylperoxyisopropyl monocarbonate,α,α′-bis(t-butylperoxy)diisopropylbenzene, etc.; carboxylates withmanganese, cobalt, zinc or the like, etc. One alone or two or more kindsof these may be used either singly or as combined. Among these, from theviewpoint of heat resistance, glass transition temperature and storagestability, imidazole compounds, organic peroxides and carboxylates maybe used; or from the viewpoint of heat resistance, glass transitiontemperature, modulus of elasticity and thermal expansion coefficient, animidazole compound may be used in combination with an organic peroxide.Among organic peroxides, α,α′-bis(t-butylperoxy)diisopropylbenzene maybe selected.

In the case where the component (E) is contained in the thermosettingresin composition of the present invention, the content ratio of thecomponent (E) is not specifically limited, but for example, the ratiomay be 0.01 to 10 parts by mass relative to 100 parts by mass of the sumtotal of the components (A) and the component (B) in the presentinvention, or may be 0.01 to 5 parts by mass. Using the component (E) inthe range tends to secure better heat resistance and storage stability.

(Flame Retardant except Phosphorus Flame Retardant (C))

Any other flame retardant than the phosphorus flame retardant (C) and aflame retardant promoter may be contained in the thermosetting resincomposition of the present invention, within a range not detracting fromthe advantageous effects of the present invention.

The other flame retardant than the phosphorus flame retardant (C) maybe, from the viewpoint of environmental issues, a metal hydrate such asaluminum hydroxide hydrate, magnesium hydroxide hydrate or the like, andone alone or two or more kinds of these may be used either singly or ascombined. The metal hydroxide may correspond to an inorganic filler, butwhen it is a material capable of imparting flame retardancy, thecompound is grouped in the category of a flame retardant.

In the case where any other flame retardant than the phosphorus flameretardant (C) is contained in the thermosetting resin composition of thepresent invention, the content ratio of the flame retardant may be 50parts by mass or less relative to 100 parts by mass of the phosphorusflame retardant (C), or may be 30 parts by mass or less, or may be 15parts by mass or less.

(Flame Retardant Promoter)

The thermosetting resin composition of the present invention may containa flame retardant promoter, for example, an inorganic flame retardantpromoter such as antimony trioxide, zinc molybdate, etc.

When a flame retardant promoter is contained in the thermosetting resincomposition of the present invention, the content ratio thereof is notspecifically limited, but may be, for example, 0.1 to 20 parts by massrelative to 100 parts by mass of the sum total of the component (A) andthe component (B), or may be 0.1 to 10 parts by mass. Containing a flameretardant promoter in such a range, the resin composition tends torealize better chemical resistance.

If desired, the thermosetting resin composition of the present inventionmay adequately contain a resin material such as a known thermoplasticresin, an elastomer, etc., as well as a coupling agent, an antioxidant,a thermal stabilizer, an antistatic agent, a UV absorbent, a pigment, acolorant, a lubricant, etc. One alone or two or more kinds of these maybe contained either singly or as combined. The amount of these to beused is not specifically limited.

(Organic Solvent)

The resin composition of the present invention may contain an organicsolvent, from the viewpoint of easy handleability through dilution andfrom the viewpoint of easy production of prepreg to be mentionedhereinunder.

Examples of the organic solvent include, though not specifically limitedthereto, alcohol solvents such as ethanol, propanol, butanol, methylcellosolve, butyl cellosolve, propylene glycol monomethyl ether, etc.;ketone solvents such as acetone, methyl ethyl ketone, methyl isobutylketone, cyclohexanone, etc.; ether solvents such as tetrahydrofuran,etc.; aromatic solvents such as toluene, xylene, mesitylene, etc.;nitrogen atom-containing solvents such as dimethylformamide,dimethylacetamide, N-methylpyrrolidone, etc.; sulfur atom-containingsolvents such as dimethylsulfoxide, etc.; ester solvents such asγ-butyrolactone, etc.

Among these, from the viewpoint of solubility, alcohol solvents, ketonesolvents or nitrogen atom-containing solvents may be used, or acetone,methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone may beused, or methyl ethyl ketone may be used.

One alone or two or more kinds of organic solvents may be used eithersingly or as combined.

The content of the organic solvent in the thermosetting resincomposition of the present invention is not specifically limited, andthe solid concentration may be 30 to 90% by mass, or may be 40 to 80% bymass, or may be 40 to 70% by mass, or may be 40 to 60% by mass. Thethermosetting resin composition whose solid concentration falls withinthe range secures good handleability and penetrability into substrate,and betters the appearance of prepreg to be produced, and the solidconcentration of resin in the prepreg to be mentioned below can bereadily controlled, therefore facilitating production of a prepreghaving a desired thickness.

The above-mentioned components (A) to (C), and the other optionalcomponents to be combined, and optionally an organic solvent are mixedin a known method to produce the thermosetting resin composition of thepresent invention. In this stage, the components may be dissolved ordispersed with stirring. The conditions for the mixing order, thetemperature, the time and others in mixing and stirring are notspecifically limited, and may be defined in any desired manner.

The glass transition temperature of the laminate formed with thethermosetting resin composition of the present invention is notspecifically limited, but from the viewpoint of good heat resistance andthrough-hole interconnection reliability, as well as excellentworkability in producing electronic parts and others, the temperaturemay be 175° C. or higher, or may be 180° C. or higher, or may be 190° C.or higher. There is no specific limitation in point of the upper limitof the glass transition temperature, and for example, the temperaturemay be 1,000° C. or lower, or may be 500° C. or lower, or may be 300° C.or lower, or may be 230° C. or lower.

The thermal expansion coefficient (in Z direction, not higher than Tg)of the laminate formed with the thermosetting resin composition of thepresent invention is not specifically limited, but from the viewpoint ofpreventing the laminate from warping, the coefficient is preferably 45ppm/° C. or less, more preferably 43 ppm/° C. or less. The lower limitof the thermal expansion coefficient is, though not specifically limitedthereto, generally 30 ppm/° C. or more, preferably 35 ppm/° C. or more.

The glass transition temperature and the thermal expansion coefficientare values measured according to IPC Standards, as described in thesection of Examples.

The dielectric constant and the dielectric dissipation factor of thelaminate formed with the thermosetting resin composition of the presentinvention are not specifically limited. From the viewpoint of favorableuse in a high frequency zone, the dielectric constant at 10 GHz ispreferably smaller, and may be 3.8 or less, or may be 3.75 or less, ormay be 3.65 or less. The lower limit of the dielectric constant is notspecifically limited, and may be, for example, 0.5 or more, or may be 1or more, or may be 3 or more, or may be 3.5 or more.

The dielectric dissipation factor is preferably smaller, and may be0.007 or less, or may be 0.006 or less. The lower limit of thedielectric dissipation factor is not specifically limited and ispreferably smaller, and may be, for example, 0.0001 or more, or may be0.002 or more, or may be 0.004 or more, or may be 0.005 or more.

The dielectric constant and the dielectric dissipation factor are valuesaccording to JPCA-TM001 (Triplate-line resonator method) as described inthe section of Examples.

[Prepreg]

The present invention also provides a prepreg including the resincomposition of the present invention and a sheet-form fiber-reinforcedsubstrate. The prepreg is formed using the resin composition of thepresent invention and a sheet-form fiber-reinforced substrate, and morespecifically, the prepreg is formed by impregnating or coating asheet-form fiber reinforced substrate with the thermosetting resincomposition of the present invention, and drying the substrate. Morespecifically, for example, the substrate is dried by heating in a dryingoven generally at a temperature of 80 to 200° C. for 1 to 30 minutes tosemi-cure the resin (into a B-stage), thereby producing the prepreg ofthe present invention. The amount of the thermosetting resin compositionto be used may be defined so that the thermosetting resincomposition-derived solid concentration in the dried prepreg could be 30to 90% by mass. When the solid concentration is controlled to fallwithin the range, the laminate to be obtained using the resultantprepreg can achieve excellent formability.

As the sheet-form fiber reinforced substrate for the prepreg, a knownsubstrate used in a laminate for various electrically insulatingmaterials is used. Examples of the materials for the sheet-formreinforced substrate include inorganic fibers of E glass, D glass, Sglass, Q glass or the like; organic fibers of polyimide, polyester,tetrafluoroethylene or the like; mixtures thereof, etc. These sheet-formreinforced substrate may have, for example, a form of woven fabric,nonwoven fabric, roving, chopped strand mat, surfacing mat, etc. Withrespect to the thickness of the sheet-form fiber reinforced substrate,there is no particular limitation, and, for example, the substratehaving a thickness of about 0.02 to 0.5 mm can be used. Further, thesubstrate having a surface treated with a coupling agent or the like orhaving a mechanically opening treated substrate can be preferably usedfrom the viewpoint of impregnation performance with the resincomposition, and from the viewpoint of heat resistance, moistureabsorption resistance, and processability of the laminate formed withthe substrate.

As the method of impregnating or coating the sheet-form reinforcedsubstrate with the thermosetting resin composition, a hot melt method ora solvent method to be mentioned below may be employed.

In the hot melt method, an organic solvent is not contained in thethermosetting resin composition, and the method is (1) a method of onceapplying the composition onto a releasable sheet, and the laminating iton a sheet-form reinforced substrate, or (2) a method of directlyapplying the resin composition to a sheet-form reinforced substrateusing a die coater.

On the other hand, the solvent method is a method of adding an organicsolvent to the thermosetting resin composition, and immersing asheet-form reinforced substrate in the resultant thermosetting resincomposition so that the sheet-form reinforced substrate could beimpregnated with the resin composition, and thereafter drying it.

[Laminate and Multilayer Printed Wiring Board]

The laminate of the present invention includes the prepreg of thepresent invention and a metal foil. The laminate of the presentinvention is formed using the prepreg of the present invention and ametal foil, and more specifically, the laminate is formed by arranging ametal foil on one surface or both surfaces of one prepreg, or byarranging a metal foil on one surface of both surfaces of a multilayerprepreg prepared by layering two or more prepregs of the presentinvention, and thereafter molding the resultant structure under heat andpressure.

Not specifically limited, the metal for the metal foil may be any oneusable for electrically insulating materials, but from the viewpoint ofelectroconductivity, the metal may be copper, gold, silver, nickel,platinum, molybdenum, ruthenium, aluminum, tungsten, iron, titanium,chromium, or an alloy containing at least one of these metal elements,or may be copper or aluminium, or may be copper.

The condition for thermal pressure forming is not specifically limited.For example, the temperature may be 100° C. to 300° C., the pressure maybe 0.2 to 10.0 MPa, and the time may be 0.1 to 5 hours. For thermalpressure forming, a method of using a vacuum press or the like to keep avacuum state for 0.5 to 5 hours may be employed.

The multilayer printed wiring board of the present invention is formedusing the prepreg or the laminate of the present invention. Themultilayer printed wiring board of the present invention can be producedusing the prepreg or the laminate of the present invention by performingcircuit formation processing and bonding processing for forming amultilayer by perforating, metal plating, etching for a metal foil orthe like according to a known method.

The thermosetting resin composition, the resin film, the prepreg, themetal-clad laminate and the multilayer printed wiring board of thepresent invention are favorably used in electronic devices working withhigh frequency signals of 1 GHz or more, and are especially favorablyused in electronic devices working with high frequency signals of 10 GHzor more.

Hereinabove, the preferred embodiments of the present invention weredescribed, but these embodiments are examples used for describing thepresent invention, and these embodiments should not be construed aslimiting the scope of the present invention. The present invention canbe practiced in various modes different from the above-describedembodiments as long as the polyphenylene ether derivative and the likeof the present invention can be obtained.

EXAMPLES

Hereinbelow, the present invention will be described in detail withreference to the following Examples, which should not be construed aslimiting the scope of the present invention.

Production Example A-1 Production of Polyphenylene Ether Derivative(A-1)

Toluene (190 parts by mass), PP0640 [polyphenylene ether having a numberaverage molecular weight of about 16,000, trade name, manufactured bySABIC Innovative Plastics Corp.] (100 parts by mass), and p-aminophenol[manufactured by Ihara Chemical Industry Co., Ltd.] (1.35 parts by mass)were charged into a glass flask container having a capacity of 2 litersand being equipped with a thermometer, a reflux condenser, and a stirrerand being capable of heating and cooling the contents of the flask, thetemperature inside the flask was set at 90° C., and the contents weredissolved with heating and stirring. After confirming the dissolutionvisually, Perbutyl (registered trademark) I [t-butylperoxyisopropylmonocarbonate, trade name, manufactured by NOF Corporation] (2 parts bymass) and manganese naphthenate [manufactured by Wako Pure ChemicalIndustries, Ltd.] (0.15 parts by mass) were added to the resultantsolution to perform a reaction at a solution temperature of 90° C. for 4hours and then cooled to 70° C. to give a polyphenylene ether compound(A) having a primary amino group at the end of the molecule.

A small portion of the resultant reaction solution was taken andsubjected to gel permeation chromatography (GPC). As a result, it wasfound that the peak derived from p-aminophenol disappeared and thepolyphenylene ether compound (A′) had a number average molecular weightof about 9,200. Further, another small portion of the reaction solutionwas taken and dropwise added to a methanol/benzene mixed solvent (massratio in the mixed solvent: 1:1) to cause reprecipitation, and theresultant purified solid material (reaction product) was subjected toFT-IR measurement. The result of the FT-IR measurement confirmed that apeak derived from a primary amino group appeared at around 3,400 cm⁻¹.

Here, the number average molecular weight was measured by gel permeationchromatography (GPC) in which standard polystyrenes were used forobtaining a molecular weight conversion calibration curve. Thecalibration curve was obtained using standard polystyrenes: TSK standardPOLYSTYRENE (Type; A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40)[trade name, manufactured by Tosoh Corp.]) and approximated to a cubicequation. Conditions for GPC are shown below.

Apparatus: (Pump: L-6200 Model [manufactured by HitachiHigh-Technologies Corporation]),

(Detector: L-3300 Model RI [manufactured by Hitachi High-TechnologiesCorporation]),

(Column oven: L-655A-52 [manufactured by Hitachi High-TechnologiesCorporation])

-   Column: Guard column; TSK Guard column HHR-L+Column; TSK    gel-G4000HHR+TSK gel-G2000HHR (trade name, each of which is    manufactured by Tosoh Corp.)-   Column size: 6.0×40 mm (guard column), 7.8×300 mm (column)-   Eluent: Tetrahydrofuran-   Concentration of a sample: 30 mg/5 mL-   Amount of a sample per injection: 20 μL-   Flow rate: 1.00 mL/minute-   Temperature for measurement: 40° C.

Then, BMI-4000 [2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, tradename, manufactured by Daiwa Kasei Industry Co., Ltd.] (4.5 parts bymass) and propylene glycol monomethyl ether (10 parts by mass) wereadded to the above-obtained reaction solution, and the temperature ofthe resultant mixture was increased while stirring, and, whilemaintaining the temperature at 120° C., a reaction was conducted for 4hours, followed by cooling and 200-mesh filtration, to produce apolyphenylene ether derivative (A-1).

A small portion of the resultant reaction solution was taken andsubjected to reprecipitation in the same manner as mentioned above, andthe resultant purified solid material was subjected to FT-IRmeasurement. The result of the FT-IR measurement confirmed that the peakat around 3,400 cm⁻¹ derived from a primary amino group disappeared anda peak of a carbonyl group of maleimide appeared at 1,700 to 1,730 cm⁻¹.Further, the solid material was subjected to GPC measurement (under thesame conditions as mentioned above). As a result, the number averagemolecular weight was found to be about 9,400.

Production Example B Production of Polyaminobismaleimide Compound (B-1)as Thermosetting Resin (B)

BMI-4000 [2,2-bis(4-(4-maleimidophenoxy)phenyl)propane, trade name,manufactured by Daiwa Kasei Industry Co., Ltd.] (100 parts by mass),Bisaniline-M [4,4′-[1,3-phenylenebis(1-methylethylidene)]bisaniline,trade name, manufactured by Mitsui Chemicals, Inc. [(14 parts by mass)and propylene glycol monomethyl ether (50 parts by mass) were chargedinto a glass flask container having a capacity of 1 liter and beingequipped with a thermometer, a reflux condenser, and a stirrer and beingcapable of heating and cooling the contents of the flaks, and, whilemaintaining the temperature thereof at 120° C. and stirring, theresultant mixture was reacted for 3 hours, and then cooled and filteredthrough a 200-mesh filter to produce a polyaminobismaleimide compound(B-1) as a thermosetting resin (B).

Examples 1 to 5, Comparative Examples 1 to 3 Preparation ofThermosetting Resin Composition

The polyphenylene ether derivative (A-1) produced in Production ExampleA, the polyaminobismaleimide compound (B-1) produced in ProductionExample B, a flame retardant, an inorganic filler, a curing acceleratorand an organic solvent were stirred and mixed according to theformulation of blending quantities (unit: part by mass) shown in Table 1at room temperature or with heating to prepare thermosetting resincompositions having a solid content (nonvolatile component)concentration of 40 to 60% by mass.

Here, the resin composition (excluding inorganic filler) generally has adensity of 1.20 to 1.25 g/cm³, and the inorganic filler used has adensity of 2.2 to 3.01 g/cm³. Therefore, when 80 parts by mass of theinorganic filler is incorporated, relative to 100 parts by mass of theresin composition (excluding inorganic filler), the amount of theinorganic filler incorporated is about 30 to 34% by volume.

<Evaluation/Measurement Method>

The thermosetting resin compositions obtained in Examples andComparative Examples were analyzed and evaluated according to themethods mentioned below. The results are shown in Table 1.

(1. Evaluation of Compatibility of Thermosetting Resin Composition)

With respect to the thermosetting resin compositions obtained in theabove Example and those dried at 160° C. for 10 minutes to remove theorganic solvent therefrom, the appearance thereof was visually examined,and the compatibility was evaluated (whether macroscopic phaseseparation or unevenness was present or not) in accordance with thecriteria shown below.

A: Macroscopic phase separation or unevenness is not present.

B: Macroscopic phase separation or unevenness is present.

(2. Formation of Prepreg and Copper-Clad Laminate)

The thermosetting resin composition obtained in each Example was appliedto glass cloth having a thickness of 0.1 mm [E glass, manufactured byNitto Boseki Co., Ltd.], and then dried by heating at 160° C. for 7minutes to prepare a prepreg having a resin content of about 54% bymass. 6 sheets of the prepared prepreg were stacked on one another, andlow profile copper foils having a thickness of 18 μm (trade name,“FV-WS”, M-side Rz: 1.5 μm; manufactured by The Furukawa Electric Co.,Ltd.) were disposed respectively on the top and bottom of the resultantlaminate so that the M-side of each copper foil was in contact with thelaminate, and subjected to hot pressing under conditions such that thetemperature was 230° C., the pressure was 3.9 MPa, and the time was 180minutes to prepare a double-sided copper-clad laminate (thickness: 0.8mm).

(2-1. Evaluation of Appearance of Prepreg)

The appearance of the above-obtained prepreg was examined. Theappearance was visually examined, and the prepreg was evaluatedaccording to the criteria shown below.

A: Nothing wrong on appearance.

C: The prepreg surface has some unevenness, streak, foaming, phaseseparation and the like, and lacks surface smoothness.

(2-2. Evaluation of Properties of Copper-Clad Laminate)

With respect to the above-obtained copper-clad laminate, theformability, the dielectric properties, the copper foil peel strength,the glass transition temperature, the thermal expansion coefficient, thesoldering heat resistance, and the flame retardancy thereof wereevaluated. The methods for evaluation of the properties of thecopper-clad laminate are as described below.

(2-2-1) Formability

The appearance of the laminate having etched copper foils on both sideswas examined to evaluate the formability. The formability was visuallyevaluated, and the laminate was evaluated according to the followingcriteria.

A: Nothing wrong on appearance.

C: The laminate has some unevenness, streak, thinned area, voids or thelike, and lacks surface smoothness.

(2-2-2) Dielectric Properties

Regarding dielectric properties (relative permittivity, dielectricdissipation factor), dielectric constant and dielectric dissipationfactor were measured at 1 GHz band and 10 GHz band according toJPCA-TM001 (Triplate-line resonator method).

(2-2-3) Copper Foil Peel Strength

Copper foil peel strength was measured in accordance with JIS-C-6481(1996) to thereby determine the adhesion to conductor.

(2-2-4) Soldering Heat Resistance

A soldering heat resistance was evaluated using a 50 mm square testspecimen having etched copper foils on both sides as follows. 3Specimens in a dry state and 3 specimens, which had been treated in apressure cooker test (PCT) apparatus (conditions: 121° C., 2.2 atm.) fora predetermined period of time (1, 3, or 5 hours), were immersed inmolten solder at 288° C. for 20 seconds, and then the appearance of eachof the resultant specimens was visually examined. The figures shown inthe tables mean, among the 3 specimens obtained after immersed in thesolder, the number of the specimen or specimens in which a defect, suchas the occurrence of blistering or measling, was not recognized in thelaminate.

(2-2-5) Glass Transition Temperature (Tg) and Thermal ExpansionCoefficient

Five mm square test pieces that had been etched to remove the copperfoil from both sides thereof were analyzed in accordance with IPC (TheInstitute for Interconnecting and Packaging Electronic Circuits)Standards using a thermomechanical analyzer (TMA) [manufactured by TAInstruments Japan Corporation, Q400 (Model Number)] to measure the glasstransition temperature (Tg) and the thermal expansion coefficient(thickness direction, temperature range: 30 to 150° C.) thereof.

(2-2-6) Flame Retardancy

The copper-clad laminate was immersed in a copper etchant, 10 mass %solution of ammonium persulfate [manufactured by Mitsubishi Gas ChemicalCorporation] to remove the copper foil, and a test piece having a lengthof 127 mm and a width of 12.7 mm was cut out of the resultant substratefor evaluation. The test piece was tested according to the test method(V method) of UL94 to evaluate the flame retardancy thereof.

Namely, the lower edge of the test piece held vertically was exposed to20-mm flame for 10 seconds, twice in every test. The evaluation wascarried out according to the criteria in the V method of UL94.

TABLE 1 Example Comparative Example 1 2 3 4 5 1 2 3 PolyphenylenePolyphenylene solid concentration 100 100 100 100 100 100 100 100 EtherEther 35% by mass Derivative (A) Derivative (A-1) Thermosetting Polyami-solid concentration 80 80 80 80 80 80 80 80 Resin (B) nobismaleimide 65%by mass Compound (B-1) Phosphorus OP-935 (phosphorus atom 8(2) Flamecontent: 23.5 Retardant (C) mass %) PX-200 (phosphorus atom 25(2)content: 28.6 mass %) PX-202 (phosphorus atom 30(2) content: 33.3 mass%) SPB-100 (phosphorus atom 16(2) 24(2) content: 18.2 mass %) HCA-HQ(phosphorus atom content: 26.7 mass %) Other Flame SAYTEX8010 (bromineatom 2(2) Retardant content: 82.7 mass %) AIOOH 53 Inorganic SC-2050 KNKsold concentration 83 98 101 90 96 78 0 76 Filler (D) 70% by mass CuringPerbutyl-P 1 1 1 1 1 1 1 1 Accelerator (E) G-8009L solid concentration 11 1 1 1 1 1 1 50% by mass Organic Methyl Ethyl 37 60 66 47 58 48 29 26Solvent Ketone Thermosetting Compatibility before evaporation A A A A AA C A Resin of organic solvent Composition after evaporation A A A A A AC A of organic solvent Prepreg Appearance A A A A A A C A LaminateFormability A A A A A A C A Dielectric  1 GHz 3.66 3.64 3.64 3.68 3.724.88 3.72 3.66 Constant 10 GHz 3.63 3.61 3.61 3.65 3.70 4.85 3.70 3.63Dielectric  1 GHz 0.0042 0.0037 0.0037 0.0043 0.0043 0.0042 0.00440.0039 Dissipation 10 GHz 0.0066 0.0055 0.0055 0.0067 0.0067 0.00660.0068 0.0057 Factor Copper Foil Peel Strength (kN/m) 0.60 0.59 0.590.61 0.61 0.55 0.57 0.65 Soldering Heat ordinary state 3 3 3 3 3 3 3 3Resistance after PCT-1 hr 3 3 3 3 3 2 3 3 treatment after PCT-3 hr 3 3 33 3 0 3 3 treatment after PCT-5 hr 3 3 3 3 3 0 3 3 treatment Glass 200180 180 200 200 170 200 200 Transition Temperature (° C.) Thermal 39 4242 41 41 55 45 41 Expansion Coefficient (ppm/° C.) Flame V-0 V-0 V-0 V-0V-0 V-0 V-0 V-1 Retardancy (The unit of content is part by mass. Forsolution (excluding flame retardant), the content is in terms of solidcontent. On the other hand, for flame retardant in the form of solution,the amount is expressed in terms of mass of the entire solution, and theparenthesized value means the content in terms of the flame retardantelement [phosphorus atom or bromine atom].)

Abbreviations of the materials in Table 1 are as follows.

(1) Flame Retardant

OP-935: aluminum dialkylphosphinate [metal salt of disubstitutedphosphinic acid, phosphorus content: 23.5% by mass, manufactured byClariant Corp.]

PX-200: 1,3-phenylenebis(di-2,6-xylenylphosphate), [aromatic phosphate,phosphorus content: 9% by mass, manufactured by Daihachi ChemicalIndustry Co., Ltd.]

PX-202: 4,4′-biphenylene-tetrakis(2,6-dimethylphenylphosphate) [aromaticphosphate, phosphorus content: 8% by mass, manufactured by DaihachiChemical Industry Co., Ltd.]

SPB-100: polybisphenoxyphosphazene [organic nitrogen-containingphosphorus compound, phosphorus content: 13% by mass, manufactured byOtsuka Chemical Co., Ltd.]

HCA-HQ:10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide[cyclic organic phosphorus compound, phosphorus content: 9.6% by mass,manufactured by Sanko Co., Ltd.]

SAYTEX8010: 1,2-bis(2,3,4,5,6-pentabromophenyl)ethane [bromine flameretardant, bromine content: 82% by mass, manufactured by AlbemarleJapan]

AlOOH: boehmite-type aluminum hydroxide [metal hydrate, density 3.0g/cm³, manufactured by Kawai Lime Industry Co., Ltd.]

The above-mentioned OP-935, PX-200, PX-202, SPB-100, HCA-HQ andSAYTEX8010 are trade names.

(2) Inorganic Filler

SC-2050 KNK: spherical molten silica, mean particle size: 0.5 μm,surface treatment: vinylsilane coupling agent (1% by mass/solidcontent), dispersant: methyl isobutyl ketone, solid concentration 70% bymass, density 2.2 g/cm³, trade name, manufactured by Admatechs CompanyLimited

(3) Curing Accelerator

Perbutyl (registered trademark) P:α,α′-bis(t-butylperoxy)diisopropylbenzene, trade name, manufactured byNOF Corp.

G-8009L: isocyanate-masked imidazole (addition product ofhexamethylene-diisocyanate resin and 2-ethyl-4-methylimidazole), tradename, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

As obvious from the results shown in Table 1, Examples of the presentinvention are excellent in compatibility of the thermosetting resincompositions and appearance of the prepregs, and the copper-cladlaminates produced using these are good and well-balanced in all theformability, the high frequency properties (dielectric properties), theadhesion to conductor, the soldering heat resistance, the glasstransition temperature, the thermal expansion coefficient and the flameretardancy.

On the other hand, as obvious from the results in Table 1, inComparative Examples, some resin compositions and prepregs are not goodin compatibility and appearance (Comparative Examples 1 to 3). Inaddition, the copper-clad laminates of Comparative Examples are inferiorto those of Examples in point of any of formability, dielectricproperties, adhesion to conductor, soldering heat resistance, glasstransition temperature, thermal expansion coefficient and flameretardancy.

INDUSTRIAL APPLICABILITY

Using a specific thermosetting resin composition and a phosphorus flameretardant along with a polyphenylene ether derivative having a specificstructure, a thermosetting resin composition having good compatibility,especially excellent high frequency properties (low electoric constant,low dielectric dissipation factor), high adhesion to conductor,excellent heat resistance, high glass transition temperature, lowthermal expansion coefficient and high flame retardancy of V-0 can beobtained.

In addition, for the thermosetting resin composition, the material costand the production cost for substrate material can be suppressed, andthe working environment is excellent, and therefore, the prepreg and thelaminate to be provided using the thermosetting resin composition can befavorably used for use for electronic parts such as multilayer printedwiring boards, etc.

The invention claimed is:
 1. A thermosetting resin compositioncomprising: (A) a polyphenylene ether derivative having an N-substitutedmaleimide structure-containing group and a structural unit representedby the following general formula (I) in one molecule, (B) at least onethermosetting resin selected from the group consisting of an epoxyresin, a cyanate resin and a maleimide compound, and (C) a phosphorusflame retardant:

wherein R¹ each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, and x represents aninteger of 0 to
 4. 2. The thermosetting resin composition according toclaim 1, wherein the N-substituted maleimide structure-containing groupis a group represented by the following general formula (Z):

wherein R² each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, y represents an integerof 0 to 4, and A¹ represents a group represented by the followinggeneral formula (II), (III), (IV) or (V):

wherein R³ each independently represents an aliphatic hydrocarbon grouphaving 1 to 5 carbon atoms, or a halogen atom, and p represents aninteger of 0 to 4:

wherein R⁴ and R⁵ each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or a halogen atom, A² represents analkylene group having 1 to 5 carbon atoms, an alkylidene group having 2to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, acarbonyloxy group, a keto group, a single bond, or a group representedby the following general formula (III-1), and q and r each independentlyrepresent an integer of 0 to 4:

wherein R⁶ and R⁷ each independently represent an aliphatic hydrocarbongroup having 1 to 5 carbon atoms, or a halogen atom, A³ represents analkylene group having 1 to 5 carbon atoms, an isopropylidene group, anether group, a sulfide group, a sulfonyl group, a carbonyloxy group, aketo group or a single bond, and s and t each independently represent aninteger of 0 to 4:

wherein n represents an integer of 0 to 10:

wherein R⁸ and R⁹ each independently represent a hydrogen atom, or analiphatic hydrocarbon group having 1 to 5 carbon atoms, and u representsan integer of 1 to
 8. 3. The thermosetting resin composition accordingto claim 1, wherein the structural unit represented by the generalformula (I) is a structural unit represented by the following formula(I′):


4. The thermosetting resin composition according to claim 2, wherein A¹in the general formula (Z) is a group represented by any of thefollowing formulae:


5. The thermosetting resin composition according to claim 1, wherein thephosphorus flame retardant (C) is at least one selected from an aromaticphosphate, and a metal salt of a disubstituted phosphinic acid.
 6. Thethermosetting resin composition according to claim 5, wherein thearomatic phosphate is represented by the following general formula (C-1)or (C-2), and the metal salt of a disubstituted phosphinic acid isrepresented by the following general formula (C-3):

wherein R^(C1) to R^(C5) each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, or a halogen atom, A^(c)represents an alkylene group having 1 to 5 carbon atoms, an alkylidenegroup having 2 to 5 carbon atoms, an ether group, a sulfide group, asulfonyl group, a carbonyloxy group, a keto group, or a single bond, eand f each independently represent an integer of 0 to 5, g, h and i eachindependently represent an integer of 0 to 4, R^(C6) and R^(C7) eachindependently represent an aliphatic hydrocarbon group having 1 to 5carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbonatoms, M represents a lithium atom, a sodium atom, a potassium atom, acalcium atom, a magnesium atom, an aluminum atom, a titanium atom or azinc atom, and m1 represents an integer of 1 to
 4. 7. The thermosettingresin composition according to claim 1, wherein the maleimide compoundas the component (B) is a polymaleimide compound (a) having at least twoN-substituted maleimide groups in one molecule, or apolyaminobismaleimide compound (c) represented by the following generalformula (VI):

wherein A⁴ has the same definition as that of A¹ in the general formula(Z), and A⁵ represents a group represented by the following generalformula (VII):

wherein R¹⁷ and R¹⁸ each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1to 5 carbon atoms, a hydroxyl group or a halogen atom, A⁸ represents analkylene group having 1 to 5 carbon atoms, an alkylidene group having 2to 5 carbon atoms, an ether group, a sulfide group, a sulfonyl group, acarbonyloxy group, a keto group, a fluorenylene group, a single bond, ora group represented by the following general formula (VII-1) or (VII-2),and q′ and r′ each independently represent an integer of 0 to 4:

wherein R¹⁹ and R²⁰ each independently represent an aliphatichydrocarbon group having 1 to 5 carbon atoms, or a halogen atom, A⁹represents an alkylene group having 1 to 5 carbon atoms, anisopropylidene group, an m-phenylenediisopropylidene group, ap-phenylenediisopropylidene group, an ether group, a sulfide group, asulfonyl group, a carbonyloxy group, a keto group or a single bond, ands′ and t′ each independently represent an integer of 0 to 4:

wherein R²¹ represents an aliphatic hydrocarbon group having 1 to 5carbon atoms, or a halogen atom, A¹⁰ and A¹¹ each independentlyrepresent an alkylene group having 1 to 5 carbon atoms, anisopropylidene group, an ether group, a sulfide group, a sulfonyl group,a carbonyloxy group, a keto group, or a single bond, and w represents aninteger of 0 to
 4. 8. The thermosetting resin composition according toclaim 1, wherein the content ratio of the component (A) to the component(B) [(A)/(B)] is from 5/95 to 80/20 by mass.
 9. The thermosetting resincomposition according to claim 1, further comprising an inorganic filler(D).
 10. The thermosetting resin composition according to claim 1,further comprising a curing accelerator (E).
 11. The thermosetting resincomposition according to claim 1, further comprising an organic solvent.12. A prepreg comprising the thermosetting resin composition of claim 1and a sheet-form fiber reinforced substrate.
 13. A laminate comprisingthe prepreg of claim 12 and a metal foil.
 14. A multilayer printedwiring board comprising the prepreg of claim
 12. 15. A multilayerprinted wiring board comprising the laminate of claim 13.